54. Rousseau Counter-Gambit 3...f5

With 3...f5 Black attacks e4 but weakens the diagonal of its own king. White defends with 4.d3 and Nc3, castles and after the exchange on c3 takes on f5: the bishop pair and the a2-g8 diagonal are its trumps.

1.e4 e5 2.Nf3 Nc6 3.Bc4 f5 4.d3 Nf6 5.Nc3 Bb4 6.O-O Bxc3 7.bxc3 d6 8.exf5

Move by move

1.e4 – Occupies the centre and frees the queen and the f1-bishop, which in the Italian Game goes to c4 to aim at the weak f7 point.
1...e5 – Black contests the centre at once: the e5 pawn controls d4 and f4 and opens the diagonal for the f8-bishop and the queen.
2.Nf3 – Development with an attack: the knight hits the e5 pawn, controls d4 and prepares quick kingside castling.
2...Nc6 – Defends e5 while developing and adds control of d4, the square White wants for a pawn.
3.Bc4 – The Italian Game move: the bishop aims at f7, defended only by the king, and controls d5, making ...d5 harder to achieve.
3...f5 – The Rousseau Counter-Gambit: Black attacks e4 with the f-pawn, but opens the a2-g8 diagonal towards its own king, exactly where the c4-bishop aims.
4.d3 – The solid reply: White defends e4 without allowing complications and keeps the bishop on the diagonal towards g8.
4...Nf6 – Black develops the knight and increases the pressure on e4.
5.Nc3 – The knight defends e4 a second time and completes development.
5...Bb4 – The bishop pins the c3-knight to the king and reduces the defence of e4.
6.O-O – White castles and breaks the pin: now the c3-knight defends e4 again.
6...Bxc3 – Black gives up the bishop for the knight, the defender of e4, and doubles White's pawns.
7.bxc3 – Recapture towards the centre: White has the bishop pair and the semi-open b-file, and the c3-pawn controls d4.
7...d6 – Black supports e5 and opens the c8-bishop.
8.exf5 – White exchanges on f5: Black will recapture with the bishop, but the a2-g8 diagonal stays open and the black king cannot castle short as long as the c4-bishop controls g8.

How to exploit the position

White has the bishop pair and the open a2-g8 diagonal: the black king cannot castle short as long as the c4-bishop controls g8. Black will recover the f5-pawn with the bishop.

Ng5 aims at the e6 and f7 squares, weakened by the absence of the f-pawn.
Bg5 pins the f6-knight to the d8-queen and increases the control of d5.
Re1 attacks the e5-pawn and prepares to open the centre with d4.
Rb1 exploits the semi-open b-file against the b7-pawn.

Master tips

Do not open the game without a reason

Against 3...f5 the reply 4.d3 defends e4 and keeps the c4-bishop on the diagonal towards the black king.